Big Sur 11.6.3 - An Error occurred migrating user data during an install

[sanmarcos]

Today's update to Big Sur 11.6.3 ended up with a boot loop into recovery mode saying "Your computer started up in Recovery because a failure occurred during installation. An error occurred migrating user data during an install. Reinstall macOS to resolve the issue".

How can a minor security update like this just brick an iMac (2017).

• I have tried reinstalling macOS Big Sur, it did not fix the issue.
• I have tried installing Monterey on top of the system using a bootable USB drive, it did not fix the issue.
• I have run Apple hardware diagnostics, everything is fine.
• Reset NVRAM
• Reset SMC (power cycling)

Any ideas that don't involve a clean install, while I do have backups, I'd rather avoid the hassle...

EDIT: I finally got some luck by booting in safe mode (with Shift), but exiting it the issue still persists.

 

[sanmarcos]

I did a clean reinstall and this fixed the issue. It also fixed my existing issue with extremely long bootup times!.

I did a full restore (using Migration Assistant) of a Carbon Copy Cloner 6 backup made wile booted in Safe Mode.

Whatever happened over years of software updates led to my system to end up in a corrupted boot state, and this last update finally bricked it.

 

[Marty_Macfly]

Hi San,

That sounds an absolute nightmare!

Bit confused, has CCC got additional functionality nowadays?

Instead of doing a full ghost image reinstall, can you now actually just reinstall backups of certain directories?!

When I first read your fix above, I assumed you did A full re-install from CCC, meaning everything was wiped, and the old image was put back in place. This would mean that you are back on the old version of the operating system?!

Hope you can advise

Well done for getting it fixed!

Regards
Martin

 

[sanmarcos]

Bootable full system backups are not supported anymore on macOS (in practice, I don't even think Apple Silicon can boot from external drives), nobody recommends them anymore. You just install the OS and restore using Migration Assistant from a file level copy of your Data partition, it is the new way of doing things, see CCC documentation. I went from a Big Sur backup to Monterey no problem using this method.